Indoor office air is an important source of worker exposure to the potentially toxic substances known as PFCs, or polyfluorinated compounds, according to a new study.

''Workers who spend their day in a typical office environment are likely to have exposure to PFCs through the air, and that seems to lead to PFC levels in their blood," says researcher Michael McClean, ScD, associate professor of environmental health at the Boston University School of Public Health.

PFCs are widespread in the environment, often found in and given off by consumer items such as furniture, carpet stain repellents, paint, and food packaging. More than 95% of people in the U.S. have been found to have some levels of the chemicals in their blood.

In recent years, research has focused on potential health hazards linked with the chemicals. Some research has linked exposure to lower birth weight and to higher cholesterol, for instance.

The Boston researchers wanted to find out where the common sources are, and decided to investigate the exposure to the chemicals in typical offices.

The study is published in Environmental Science & Technology.It was funded by the National Institute of Environmental Health Sciences.

PFCs in the Office: Study Details

During the winter of 2009, McClean and his colleagues sampled the air in 31 Boston offices for four days. After that, they took a blood sample from each of the 31 workers. The researchers wanted to see if the PFCs in the air correlated with the PFCs found in the workers' blood.

Workers had to be in the office at least 18 hours a week to participate, McClean says.

The researchers analyzed the air samples for many PFCs, including fluorotelomer alcohols (FTOHs), sulfonamides (FOSAs), and sulfonamidoethanols (FOSEs).

They analyzed blood samples for 12 PFCs, including PFOA (perfluorooctanoate) and PFOS (perfluorooctane sulfonate), two very common PFCs.

"Most of our participants came from two buildings," McClean says. One was relatively new, the other building older but with some new carpeting.

The FTOHs were highest in the air samples. The researchers found that concentrations of FTOH were three to five times higher than levels reported in prior studies of household air.

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In the blood samples, the PFC called PFOA, a breakdown product of FTOHs, was linked with the office air level of the FTOH.

These findings might suggest that office air is a unique and also important exposure source, the researchers say.

''We found that the levels found in the air are different by building; the levels measured in blood are also different by building," McLean tells WebMD.

Those workers in the new building had the highest levels of PFCs in the blood, McClean found. The newer building had newer furniture, paint, and carpeting. The next highest levels were in workers with offices in the partially renovated building. Those in the older building with no new furniture or carpeting had the lowest levels.

The researchers found only a link, McClean tells WebMD, not a cause and effect. "We can't say whether A causes B," he says.

Levels found were consistent, he says, with the levels found in the general population, wherever they may work.

PFCs at the Office: Perspectives

''The new study is really important," says Olga Naidenko, PhD, a senior scientist at Environmental Working Group, an advocacy organization. "Up to this point, there has been debate among researchers about from which sources PFCs get into our bodies," she says. "This class of chemicals, they are all over the place."

Finding the sources of the chemicals is crucial, she says. "We need to get this stuff out [of consumer goods]," Naidenko tells WebMD. "We should not be exposing our workers to these chemicals."

Health effects have been found, she says, even with low blood levels of PFCs.

PFCs in consumer goods such as carpeting do not dissipate quickly, she tells WebMD. Consumers can check before they buy items such as carpeting, asking if any PFCs (from stain repellents) are in the item. However, she concedes, sales people do not always know.

Janet Smith, a spokeswoman for DuPont Chemicals and Fluoroproducts, declined to comment at length. On its web site, DuPont states that it has reduced PFOA emissions at manufacturing sites worldwide by 98%. It says it is developing alternative stain repellents.

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In an email statement, Smith tells WebMD: "The term 'PFCs' is rather a broad umbrella, grouping together chemicals that have different properties and applications, and different toxicity and environmental profiles. These chemicals should be considered individually when discussing questions about health and safety."